why does a curry stain on white cloth becomes reddish-brown soap is scrubbed over it n then it turns yellow again if washed with plenty of water ????
The curry might contain turmeric powder which is an indicator of acids and bases.
Soap being basic in nature turns the colour of the turmeric from yellow to reddish-brown.
After washing with lots of water the soap is removed and the turmeric returns to its yellow colour.